Today there are many different technologies for obtaining diamond crystals, for a wide variety of applications, in various sizes, colors and strengths.
Diamond is nothing more than pure carbon with a special crystal lattice.
Another representative of pure carbon on Earth is charcoal, graphite.
Carbon Characteristics:
Atomic weight of carbon 12.011;
The serial number in the periodic system of Mendeleev is 6;
Number of electrons 6;
basic valence 4;
At normal atmospheric pressure it does not pass into liquid;
When heated at normal pressure to a temperature of 3670 0 C, carbon;
turns into gas, bypassing the liquid state.
Diamond Characteristics:
Density 3.5 g. cm 2;
Refraction of light 2.42 (Glass 1, 8);
Hardness 2,000,000 arb. units (Steel 30,000, glass 40,000 relative to talc whose hardness = 1);
The temperature of transition to graphite in open air is 1200 0 C;
Ignition temperature in pure oxygen is 740 0 C;
The unit of measurement for diamonds is carat. One carat is equal to 0.2 grams. Diamond, dimensions 1 x 1 cm = 17.5 carats;
In diamond, each carbon atom is connected to 4 other carbon atoms and the distance between them is exactly the same = 1.54 angstroms. Carbon atoms in diamond are located at the corners of a regular tetrahedron of the atomic crystal lattice.
The temperature of carbon evaporation is 3670 0 C (diagram 1); the critical point (Z) (temperature 3670 0 C. pressure -120 atm.) is called the first point of the triple state.
At this point, carbon can transition into a solid, gaseous or liquid state.
With increasing pressure and temperature, we obtain the second triple point (D), in which the state of carbon in the form of crystals is possible ( diamond), in the form of a liquid and an amorphous state (graphite).
The best result of obtaining diamonds during the transition from the liquid state of carbon to the crystalline state is a decrease in temperature, but, if possible, leaving a very high pressure. Great value in diamond production technology are played by the time characteristics of the process.
As previously noted, carbon does not exist in the liquid state under normal conditions (760 mm Hg and 20 0 C). Carbon in a liquid state is possible and exists only at pressures above 120 atm. and 3740 0 S. ( diagram 1).
From physical properties diamond It should be noted that the combustion temperature in an oxygen environment is 670 0 C; basically, the diamond burns without a residue.
When heated diamond above 1200 0 C without air, the graphitization process begins diamond, this is what happens when the process technology is incorrect diamond production.
Methods for producing artificial diamond crystals
The first way to get artificial diamonds is a method close to natural occurrence natural diamonds, this is a combination of very high pressure and high temperature.
The first method is the most reliable, but also the most technologically complex
Below is one of the laboratory installations for obtaining crystals diamond as close as possible to the expected natural pattern of occurrence diamonds in the earth's thickness - powerful pressure, high temperature.
Annex 1.
 |
 |
Laboratory installation upon receipt artificial diamonds is a high pressure press. A working cylinder is inserted into the press body.
This cylinder has drillings for refrigerant circulation and holes for pressurized water supply. A chamber made of tantalum carbide is inserted into this body, in which a workpiece is placed - graphite, which should turn into diamond.
A copper busbar supply is provided to supply electric current to the working chamber.
Diamond production technology occurs in several stages.
First, after installing the cylinder in a high-pressure press, water is supplied and the process of pre-compression of graphite with water pressure occurs, to approximately 2-3 thousand atmospheres. In the second stage, refrigerant is supplied and the water is frozen to a temperature of minus 12 degrees Celsius.
In this case, additional compression of graphite up to 20 thousand atmospheres occurs due to the expansion of ice.
At the next stage, a powerful pulse of electric current lasting 0.3 seconds is applied.
At the final stage, defrost the ice and remove diamonds.
Obtained in this manner diamonds They are mostly dirty in color, have a porous structure, and the shape of the crystals is tetrahedral.
Mostly stronger natural diamonds and mainly serve for technical purposes.
Second way
The second method, perhaps technologically simple, but complex in terms of the equipment used, is the method of extension diamond crystals in a methane environment (CH 4).
In this method, a diamond crystal is heated to a temperature of 1111 0 C and blown with methane. The pressure in the working chamber can be small, about 0.1 technical atmosphere. This pressure mainly serves to prevent atmospheric oxygen from entering the chamber.
It must be remembered that starting at 1200 0 C, diamond begins its transition to the graphite state (without access to carbon).
The diamond crystal growing process occurs on the hot surface of the diamond by adding carbon atoms to the existing crystal lattice of the diamond seed crystal. The amount of carbon (diamond) released is 0.2% from the surface of the seed crystal in one hour.
The shape of the crystals obtained in this way is cubic, in contrast to natural tetrahedral, the color is black, the strength is comparable to natural diamonds. At its core, it is pure carbide, but is called diamond due to the very high hardness of the resulting crystals, and due to the fact that real diamonds are used as the seed crystal.
The third method of obtaining diamonds is the explosion method.
This method produces very fine diamond dust for the production of sharpening stones and abrasives. Either an explosion of a “conventional” explosive or an explosion of a wire with a large current pulse is used.
To obtain a dense detonation wave, you need a membrane that breaks at the speed of sound in the metal from which the membrane is made (for iron this is 5000 m/sec.).
The “heated” graphite located on the so-called “frying pan” at the moment of passage of the detonation wave turns into diamond crystals.
This method gives a much higher yield as a percentage of the amount of graphite than the high pressure method.
The crystals are colorless, pure water, transparent, but very small (30 - 50 microns). Crystal shape tetrahedral strength comparable to natural diamonds.
The essence of this method of obtaining diamonds, by the explosion method, is that when an explosive is detonated in a confined space, the detonation wave upon impact with an obstacle on the boundary layer, the shock wave - the obstacle, simultaneously creates high pressure and high temperature. Pressure can reach over 300,000 atm, temperature tens of thousands of degrees. Unfortunately (or fortunately), all this takes place in millionths of a second and the size (thickness) of the detonation wave does not exceed 10-30 microns.
At the moment the membrane ruptures, the shock wave acquires “density” and a kind of quality called homogeneity.
Some diamond crystals those obtained in a similar way can have a diameter of up to 50 microns. Of great importance in this method is the bed on which the heated graphite is located and the thickness of the working layer.
Interesting experiments on “secondary” pressing of the obtaineddiamondsusing the same explosion method, according to the principle of powder metallurgy. IN in this case, Vdiamond production, you can obtain crystals of various sizes and weights fromdiamondpowder. The vast majority of crystals are cloudy in color. The fragility of the resulting secondarydiamond crystals. The strength is much lower than natural ones; “surprises” are possible during processing. In this case, greed can ruin the idea in the most literal sense of this understanding. It is not recommended to exceed the thickness of graphite 60 microns.
The fourth method of producing diamonds uses catalysts
Application of catalysts in diamond production significantly helps reduce pressure and temperature. Diamond crystals are formed in the separating layer between hot graphite and the catalyst metal film. With appropriate selection of technologies, you can obtain up to 50 grams technical diamonds in one technological cycle.
As we see, from diagrams 3 , Appendix 3
Arising at the graphite-catalyst transition boundary, diamond crystals continue to grow under constant conditions in the working chamber until the catalyst metal film continues to combine with graphite.
Appendix 3
Crystal growth continues in the alloying metal itself due to the penetration of carbon atoms through a thin film of the metal.
Artificial diamonds those obtained in this way are very small crystals ( 30 -200 microns).
Received with low temperatures diamond crystals have square shape The structure of the crystals, black in color, is equal or superior to natural ones in strength.
Crystals obtained from high temperatures at high pressures they have an octahedral shape, the color is different - yellow, blue, green, white, transparent and opaque crystals. The strength is equal to or superior to natural diamonds. The influence of catalysts on color is obvious. Nickel impurity in diamond crystals gives greenish tones to diamonds, beryllium additives give diamonds blue tones colors.
It should be noted that in terms of hardness there is no element in the world harderdiamond, although in other properties it may be inferior to some artificial elements. The table shows elements that can give a more complete picture of some properties diamond in comparison with other earthly elements.
Greetings, our dears! Everyone has heard the famous phrase “ Best friends girls are diamonds.” These are not just throwaway trinkets, but the most durable investment, which is also a fashionable decoration. Sometimes it costs him a fortune, which takes a long time to save for, and expecting a gift from a random rich admirer is completely stupid. But there is an excellent alternative - an artificial diamond, which looks no different from a real one, but costs several times less.
Today you will learn not only about the types and methods of obtaining this stone in artificially created conditions, but also try to make it yourself at home... in the microwave!
Everyone is interested in the name in the jewelry world of a stone created not by nature, but by human hands. “Obviously it’s a fake,” you’ll say, and you’ll be wrong. The point is that it is necessary to distinguish between the artisanal production of fakes and a high-tech process that gradually repeats the appearance of a precious gem. For this, expensive equipment and high-quality raw materials are used. The result is a perfect diamond that even an experienced specialist cannot distinguish from a natural one.
Common features of natural and synthetic diamond
The continuous production of these stones had a double impact on the stone mining industry. On the one hand, the “twin brother” of a real diamond solved the problem of shortage natural stones. On the other hand, dishonest sellers now have the opportunity to pass off “artificial” items as real stone and make huge money from it.
We’ll learn a little later about how to distinguish the art of nature from the craftsmanship of the modern diamond industry, but for now about the common features of artificial and natural diamonds.
They are almost identical in:
- Physical properties, atomic structure, chemical composition;
- Transparency, degree of thermal conductivity, purity of the crystal lattice;
- Feedstock for manufacturing (crystallized pure carbon);
- Appearance.
If you are presented with a ring with a “brilliant” and they assure you that it is nothing more than “gold and diamonds,” you will never suspect deception. Even an experienced jeweler under a magnifying glass sometimes will not be able to discern traces of the artificial origin of a stone, especially if it is white, because a transparent artificial diamond without admixtures of other colors cannot be distinguished from a natural one.
Multifaceted palette of synthetic diamonds
A completely transparent diamond is considered the rarest and most expensive. Although stones with shades are also in demand and attract the eye with their mesmerizing beauty.
Today the world produces several types of colored artificial diamonds:
- Blue (from pale to rich heavenly shade, which is obtained by adding boron to the composition; reaches 1.25 carats);
- Yellow (from light lemon to rich bright yellow and even orange; this palette is formed by nitrogen; such diamonds can reach 2 carats and are much easier to grow than blue ones);
- Pink, red, lilac, green (depending on the addition of various impurities during processing, you can get diamonds of the most incredible shades).
A little history about artificial diamonds
The first “counterfeits”, substitutes for natural diamonds, were recorded back in 1920.
Charles Parsons invented the prototype of the current synthetic crystal. It was so superbly performed that it ended up in the necklace of the famous Sybil Shepherd. The decoration later became one of the relics of the British Empire. It is interesting that no one else has succeeded in replicating that very first “fake” diamond, although the author himself was not too pleased with his creation.
Before World War II, two US companies decided to mass produce diamonds. In laboratory conditions, they conducted the first experiment using carbon. The starting material was subjected to pressure and high temperatures. The ardor of inventors subsided during the war, although many researchers are sure that diamonds were needed specifically for military needs, and then the need for them disappeared.
Known for its diamonds is QUINTUS, a project of Swedish businessmen. It is he who owns a huge batch of stones. They were used mainly in industry, since they were not very beautiful for creating jewelry, even rough, and did not reach the aesthetics of jewelry.
The first precious diamond was created in Tokyo in 1997. It was smoky, with shimmer and a yellowish tint characteristic of real stone. Today Japan controls about 8% of the world's diamond production. The USA and China are rightfully considered “monsters” in the field of stone synthesis.
Now this is a full-scale production, allowing jewelry lovers to sparkle with luxurious jewelry. Pebbles grown in “incubator” conditions are inserted into pendants, rings, and used to decorate clothes and shoes. At the same time, their cost does not hit the budget so much.
Owners of large jewelry chains do not share much enthusiasm for the massive flooding of the market with “counterfeits.” It is estimated that they will lose more than 15% of the profits from the sale of natural stones.
If you are picky and want to have real diamonds and are willing to pay for their natural origin, we advise you to know by sight all their synthetic substitutes.
Diamond doubles and how to distinguish a “fake” stone from a natural one
One of the most common fake diamonds these days is cubic zirconia. It was first obtained in 1976 and is zirconium dioxide. Cubic zirconia shimmers exactly like real diamonds, and is used everywhere in the modern jewelry industry. Usually sellers indicate the name of the stone on the price tag, but unscrupulous traders can pass it off as precious. How to distinguish cubic zirconia from natural diamond? It’s very simple: you need to weigh two identical stones (natural and substitute). The real one will weigh more due to its greater density, while cubic zirconia will be lighter.
It is believed that the latter can also be calculated using ultraviolet radiation. When exposed to it, cubic zirconia acquires a green-yellow hue.
Moissanite is a more expensive analogue of diamond. It is almost impossible to distinguish them. The scientific name of moissanite is silicon carbide, which is transformed with modern equipment into a magnificent shining gem.
The discoverer of this stone, Henry Moissan, was awarded the Nobel Prize. He was the first to find meteorite fragments in the crater of a volcano, which later became raw materials for diamond production.
How to recognize this “double” and not be deceived when purchasing? A natural diamond, oddly enough, is not ideal in appearance. Its surface is slightly rough, in contrast to the smooth shell of moissanite. If you look closely, you can find a black reflection of diamond fragments, while in a synthetic stone there are no foreign inclusions.
Among other diamond substitutes, zircon, white sapphire and topaz, and yttrium aluminum garnet are in use today.
Well, we can’t help but mention the well-known “glass” or rhinestones. Previously they were made from natural rock crystal, and now from simple glass and polymers. Back in the 18th century, Georg Friedrich Strass came up with the idea of applying metal powder to the underside of crystal, thereby achieving a mirror-like diamond effect. Real rhinestones are not considered today in bad taste. What are the famous products from Swarovski worth, who strive to get all the famous beauties of the world into their collection!
Do not underestimate all types of substitutes; they have their value in the jewelry world. In addition, their production is a very labor-intensive process, which allows us to obtain magnificent specimens that are not inferior to natural stones in aesthetic qualities.
Heat, gas and pressure
Let's delve a little deeper into the technical process itself, and then find out how to get a diamond at home. Let’s master, so to speak, the profession of jewelry technologists in order to understand how complex and painstaking work it is.
Today, there are two methods for producing diamond in a laboratory.
- Diamond powder is placed in a special capsule, which dissolves under pressure and high temperatures. Then the crystallization process occurs, which takes up to several months. The result is diamonds with cubic facets, different from real ones not only in shape, but also in the growth process itself.
- The second method also involves the presence of a chamber filled with gas. When exposed to energy flows, gas molecules in a vacuum are destroyed, and carbon atoms settle inside the capsule in the form of plates. In a large enough chamber, dozens of diamonds can be grown in a few weeks. They will be flaky, with rough black edges. Sometimes stones with this method are obtained with a brown tint, but all impurities are well cleaned during the heat treatment process. Then the craftsmen begin cutting.
Growing a diamond at home
As you can see, the process is very interesting, good craftsmen earn fabulous sums in the diamond industry. Are you ready to try yourself in this profession? Then let's start our experiment.
We will need:
- Microwave;
- 3 pencil leads (graphite), about 3 mm thick;
- 15 cm cotton thread;
- 2 mugs;
- Olive oil.
And now the action itself:
- Drop some into a small saucer olive oil, place a thread around its perimeter so that it absorbs the excess.
- Now lift the thread a little and tie it into a weak knot. Let's pass a graphite rod into it. You can place it on 2 toothpicks so that it is just above the surface of the oil. You can gently pull both ends of the thread, tying a tight knot. Leave this entire structure for half an hour.
- Wash and dry the microwave thoroughly; there should be no food residue or dust.
- Turn the mug over and place it in the microwave. Place the two remaining rods on it, and the prepared oil rod across them. Cover the top with a second mug. Turn on the stove at maximum temperature and time.
- In the end, the unoiled rods will remain untouched, and the area that was impregnated will melt and a diamond will form in its place. You cannot touch the structure with your hands right away, otherwise you risk getting burned.
You can admire your own creation, and even if this creation does not exactly resemble a jewel, but rather a craft from the “young chemist” set, but you have learned the basics of “stone processing” and “diamond mining”.
How to choose correctly
In the matter of buying jewelry, each of us can hardly be called an expert, so it is better if you purchase jewelry in trusted jewelry stores of well-known retail chains.
Agree, buying a fake glass diamond along with a diamond is not very pleasant. It is believed that all real diamonds have a special marking. In addition, they weigh more than synthetic ones and have a different crystal lattice. Counterfeits are sometimes more flawless in appearance, without impurities and with a perfectly smooth surface; they can react to strong magnets, so just in case, before purchasing, conduct an experiment right in the store. If you want to be 100% sure, take the stone for examination to a gemologist, a diamond specialist. He will certainly be able to determine whether the person in front of you is artificial or not.
However, wearing unnatural stones now is not at all shameful, especially if your budget does not allow you to buy luxurious real diamonds. A necklace or earrings with cubic zirconia or rhinestones will shine even brighter than their natural counterparts, and will cost several times less than products with diamonds.
So, today we have become familiar with what diamond substitutes are and “what they are eaten with,” or rather, how they originated and how they are produced. We have learned how to independently mine a diamond from a simple pencil and can rightfully consider ourselves experts in this topic.
Team LyubiKamni
Another method (CVD), which began to be used to produce artificial diamonds, differs in that the entire process occurs at a lower level of pressure and in a shorter time. The starting material is immersed in a special chamber where vacuum conditions are created. Then the exposure to microwave rays and gases begins. Carbon plasma heats up to 3000 degrees. Synthetic diamonds are formed by deposition of carbon molecules onto a blank plate.
Substances rich in carbon are used as raw materials. It can be graphite, sugar coal, soot. Artificially grown stones have the same structure as natural ones. And this explains their hardness and high strength.
Areas of use
In my own way appearance An artificial diamond is no different from a real natural mineral. However, its cost is significantly less. Such stones, obtained in a laboratory, are better suited for cutting. Jewelers can cut even very small synthetic crystals. Such small samples are in great demand, because natural small crystals are very difficult to extract from the rock.
The high levels of hardness and strength that characterize artificially grown diamonds make them indispensable for use in creating various devices for cutting or grinding. Diamond coating and chips are present today on saws, drills, drills and many other tools. Now such material is actively used in the production of microcircuits.
The production of synthetic diamonds by CVD is very important, as the resulting material is used to create high-tech medical equipment. The use of such components allows you to extend the service life of devices, since diamond parts can withstand high heat, maintaining efficiency and performance.
Variety of species
High demand for beautiful jewelry with sparkling, iridescent stones naturally led to the appearance of various imitations of diamond. Sometimes instead gemstone in jewelry they used a transparent variety of quartz - rock crystal, white sapphire. But with the development of technology, artificial diamonds appeared, which were not much different from a real stone. .jpg" alt="imitation diamond" width="200" height="213">!} 
A diamond substitute obtained in a laboratory contains, in addition to carbon atoms, nitrogen in its crystal lattice, inclusions of which appear there during the growth stage. Due to the fact that nitrogen suppresses the blue spectrum, artificial stone takes on a tint yellow color. Now there are the following varieties:
- Back in the seventies of the twentieth century, cubic zirconia appeared in the jewelry industry. This diamond imitation was cubic stabilized zircon. In terms of its optical properties, it is very similar to the natural sample, but is significantly inferior to it in strength.
- Another option for imitation diamond is Nexus. When it is produced, carbon combines with various impurities. The sample is distinguished by high strength and hardness.
- Moissanite obtained from silicon carbide is the most expensive. It has extraordinary shine and excellent strength.
Products using imitation diamonds are always in high demand. However, even when choosing jewelry that uses artificially grown stone, you need to be careful. Unscrupulous sellers may sell ordinary glass that has been cut.
How to distinguish imitation
When buying any jewelry in a jewelry store, you can ask the seller for documents that confirm the authenticity of a particular item. And if the product uses an artificially grown crystal, then you should receive complete information about this.
If you doubt that this is a natural diamond, you can try to check it at home:
- The first thing you should pay attention to is the number of edges. When cut, cubic zirconia receives fewer edges, which are also more rounded.
- You can place a drop of oil on the test sample. On a natural pebble it will remain unchanged. And in imitation, it will disintegrate into small particles, and then gather into small droplets.
- If you dip a crystal in oil and then attach it to a glass surface, the real one will stick to it, but this trick will not work.
- Try placing the crystal on newspaper. Through cubic zirconia you will see letters, but through diamond you will not.
- A natural stone, squeezed in your hand, will remain cool when the imitation quickly reaches body temperature.
- Examine the crystal. Natural diamonds are extremely rarely homogeneous; they always contain inclusions and small defects. Whereas cubic zirconias are always absolutely transparent.
Interestingly, cubic zirconia, although not possessing a unique diamond shine, casts glare much better. But if you doubt the origin of the stone, it is best to turn to professionals. Using modern equipment, gemologists will tell you the result, the accuracy of which will be 100%.
EE "BELARUSIAN STATE ECONOMIC UNIVERSITY"
Department of Technology of Major Industries
Individual task
on the topic: Production of artificial diamonds
Abstract. 3
Introduction. 4
Chapter 1. Natural diamonds... 5
1.1 Carbon nature of diamond. 5
1.2 Natural deposits. 6
1.3 Diamond price. 7
Chapter 2. Development of diamond production technology. 9
2.1 The need for industrial production of diamonds. 9
2.2 Stages of development. 10
2.3 Temperature gradient method. eleven
2.4 Application of tisnumite. 13
2.5 Modern technologies. 15
2.6 Chemical treatment. 17
2.7 Radiation treatment. 17
2.8 Thermobaric treatment. 18
2.9 Controlled synthesis. 18
2.10 Control of the origin of diamonds. 20
Conclusion. 22
List of sources used. 23
Key words: diamond, brilliant, tisnumite, cut, kimberlite, graphite, crystal, impurities, synthesis.
This work provides general information about the properties and nature of diamonds, their largest deposits and mining methods; on the development of technology for the production of artificial diamonds and their application, as well as on modern technologies cultivation and processing of diamonds.
Introduction
Diamond is an absolutely irreplaceable material in the most different areas human activities, ranging from the jewelry and manufacturing industries to electronics and space. And all this is thanks to him unique properties: hardness and wear resistance, high thermal conductivity and optical transparency, high refractive index and strong dispersion, chemical and radiation resistance, as well as the possibility of doping it with electrically and optically active impurities. Large and extremely pure natural diamonds are very rare, so it is not surprising that successful attempts to produce them are of great interest.
Diamonds are used in many industries as an abrasive material. The high cost of natural diamonds necessitates the production of synthetic stones on an industrial scale. Their annual production amounts to several million carats. And most of them are used for technological needs.
The purpose of the work is to study the technology of production and processing of synthetic diamonds. To do this, the task is to highlight the history of the development of the industry, consider the main technological processes of production and methods of processing artificial diamonds, and also show the various areas of application of such diamonds in industry and modern nanotechnologies.
1.1 Carbon nature of diamond
For a long time, diamonds were considered miraculous stone and a powerful talisman. It was believed that the person wearing it retains memory and a cheerful mood, does not know stomach diseases, is not affected by poison, and is brave and faithful.
Diamond is the hardest mineral (hardness 10 on the mineralogical scale; density 3.5 g/cm3) with a high refractive index of 2.417. In addition, diamond is a semiconductor. In air, diamond burns at 850 oC with the formation of CO2; in a vacuum at temperatures above 1500 oC it turns into graphite. The properties of diamond change dramatically depending on the presence (type I) or absence (type II) of nitrogen impurities. Type I is characterized by anomalous birefringence, low photoconductivity, lack of electrical conductivity, absorption in the infrared (between 8-10 μm) and ultraviolet (from 3300 A) ranges, and high thermal conductivity. Nitrogen-free diamonds (type II) are practically isotropic, have high photoconductivity, do not absorb infrared radiation and are transparent in ultraviolet (up to 2200 A), and have extremely high thermal conductivity. X-ray diffraction reveals additional lines in the first type, indicating a “defect” in the crystal structure.
It's hard to imagine that the hardest known natural materials is one of the polymorphic (differing in the arrangement of atoms in the crystal lattice) modifications of carbon, another modification of which is graphite, a soft substance used as a lubricant and pencil leads. In diamond, which has a cubic structure, each carbon atom is surrounded by four of the same atoms, which form a regular tetrahedral pyramid. Graphite has a layered structure in which strong connections between carbon atoms exist only inside the layer, where the atoms form a hexagonal network. The connection between the individual layers is very weak, so they can easily slide relative to each other and remain on the paper in the form of microscales when we write with a pencil.
Diamonds originated and grew billions of years ago at depths of 150-200 km under the influence of high temperatures and pressures. Conditions for their growth, as a rule, persisted for several million years, and then increasing pressure ejected them closer to the earth's surface. After which they either remained in place (in “primary” deposits), or under the influence of wind and water they were removed from the rock and accumulated in secondary (placer) deposits. Until the mid-20th century, the main diamond production came from alluvial deposits. They were much easier to find and develop. However, these deposits are usually small and quickly depleted. After 1990, more than 75% of world diamond production began to come from primary deposits, the so-called kimberlite pipes. These cone-shaped, tapering rock deposits acted as a kind of conveyor, delivering diamonds to the surface of the earth. The area of exposure of kimberlite bodies to the surface varies. The largest kimberlite pipe, Mwadui, in Tanzania has a diameter of ~1-1.5 km. The depth of development of the pipes reaches 1 km. However, not all kimberlite pipes are diamond-bearing. Only those in which the diamond content is 0.5-5 carats (0.1-1.0 grams) per ton of rock are profitable. The vast majority of diamonds usually range in size from fractions of a millimeter to 4-5 mm, and their weight is less than a carat (0.2 grams).
Currently, mineral extraction is carried out in 26 countries of the world, the largest of which are Russia (Yakutia and the Urals), Botswana, South Africa, Zaire and Namibia. An average of 100-110 million carats (20 tons) are mined annually in the world. IN last years Russia has taken first place in the production of natural diamonds and second in terms of their total value. According to the Ministry of Finance, the volume of diamond production in Russia in the first half of 2004 amounted to 17.7 million carats at an average price of $51 per carat (0.2 grams). Exports of rough natural diamonds from the territory of the Russian Federation in January-September 2004 amounted to 23.6 million carats. The share of jewelry diamonds is 20-25%. The bulk (75-80%) of the mined stones are so-called technical ones. Diamonds in this category, due to their high abrasive qualities, have found wide application in the manufacturing and drilling industries. The largest jewelry diamond in the world, the Cullinan, weighing 3106 carats (621.2 grams), measuring 5.5x10x6.5 cm, was found in 1905 in the Transvaal (South Africa). Subsequently, 9 large diamonds were made from it (the largest “Star of Africa” is 530.2 carats) and 96 small ones. During the cutting process, 66% of the original mass of the crystal was lost.
Diamonds (cut diamonds) are graded according to four main CCCC criteria (the so-called 4’C system): color (color), quality (clarity), cut and proportions (cut), carat weight (carat weight). The most valuable are those that have a so-called “high” color, but in reality are colorless. The presence of even a barely noticeable and insignificant, in the eyes of a non-specialist, shade of yellow, brown or green (called “color” by jewelers) can seriously reduce the value of a stone. For colorless diamonds, the most valued is the round cut (the diamond in this case has 57 facets), which allows the brilliance and play of the stone to be revealed to the maximum (the so-called “fire”). The maximum cost of a 1-carat diamond today is $18,000. Most often, stones of the same weight are of lesser color and quality, and their cost is $5,000-$8,000.
Figure 1.1. Colored diamonds
The champions in value in the world of diamonds are stones colored red, blue, pink, green and orange. The price of pink and blue diamonds can exceed the cost of colorless diamonds of similar weight and quality by 10 times or more, and the most expensive (per carat) diamond in history is a red stone weighing 0.95 carats, sold in 1987 at Christie's for 880 000 US dollars. There is no single price list for colored stones, and, as a rule, they are formed at auction.
The high price of these stones is explained not only by their special characteristics, but also by the level of monopolization in trade: the De Beers International Corporation, which controls 70-80% of natural diamonds supplied to the market, has maintained known prices for them for more than a century. The development of industrial production of technical and jewelry analogues in the second half of the 20th century did not reduce the cost of diamonds on the world market.
Only small stones with a diameter of up to 0.6 mm are grown in industrial quantities, used as raw materials for the manufacture of abrasive tools. Prices for them fell slightly after the development of this technology and amount to about 10 cents per carat. A decrease in prices for jewelry diamonds is not expected, since their cultivation is quite expensive.
The phrase “Belarusian diamonds” sounds the same to our ears as “Belarusian shrimp.” But don't rush into jokes. Few people know that in the nineties, one of the world’s first diamond synthesis plants was built in Belarus, that the world’s industrial giants are ready to chase Belarusian scientists in this field, and that the quality of crystals was appreciated at the international level.
The world's first synthesized diamond was produced by General Electric back in the 1950s using a special press. The small dirty pebble was no different in properties from natural diamonds. There was only one catch: it needed much more money to synthesize it than to extract it from nature. They gave up on this matter and happily forgot about growing diamonds until the 1980s.
One of the first attempts to produce diamonds using an electric arc furnace. At the end of the 1980s, scientists from the Novosibirsk branch of the Russian Academy of Sciences created a pressless "cut sphere" (BARS) apparatus, with the help of which, for the first time in the world, they obtained a synthesized diamond, ready to compete with natural diamonds not only in quality, but also in cost. For the first synthesized Novosibirsk diamonds, it was significantly lower.
Retired general, seven scientists and $5 million
After successful testing in the 1990s, seven famous Soviet scientists (two of them were Belarusians) got the idea to create the world's first diamond synthesis plant. Due to its good geographical location, Belarus was chosen as the site.
Scientists became the founders of the Adamas company. They took out a loan for 51 million Soviet rubles from Promstroybank of the USSR and began
construction in the village of Atolino, near Minsk.
BARS devices.
The plant was supposed to be quite large: a three-story building, 220 workers. But there wasn’t enough money, so later the founders included the then Belpromstroybank, which provided the company with a credit line of $5 million, as well as two well-known Soviet times businessmen who contributed another $2.5 million.
The investors only managed to complete the building, supply 120 BARS devices and work out the technology a little, when problems began for the founding businessmen - they left the plant without money.
Unexpectedly, four scientists are lured to the United States by retired General Carter Clark. It turns out that in 1995 he bought the technology for producing synthesized diamonds for $60 thousand and founded the Gemesis Diamond company. By the way, everything was formalized, since Russia at that time urgently needed money and was selling off its scientific developments.
The scientists left the Adamas and went to Clark.
One of largest producers synthesized diamonds in the world.
Finding themselves in a difficult situation, the founders tried to return the loan
money to the bank, but in vain. In 1999, regarding the management of Adamas
a criminal case was opened. The proceedings lasted for five years, the amount of damage
was estimated at $7 million. Businessmen and a lawyer went abroad. However, four
nevertheless they imprisoned me.
After their release, none of the former Adamas leaders in
Atolino did not return. The remaining three left for St. Petersburg and Moscow
scientists, and with them the technology of diamond synthesis.
The first synthetic diamonds.
This is how three largest centers of synthesized diamonds appeared in the world:
Moscow, St. Petersburg and the American state of Florida. There are a few more small ones
companies, but they say that all the threads lead to the same seven.
What has been happening to the plant itself all this time? It was transferred to balance
Belarusian State University. In one of the parts of the building there was a
enterprise RUE "Adamas BGU": scientists conducted research, studied
production of technical diamonds, improved it. Is it true,
the operation of the installations was very expensive and a financial issue
became more and more acute.
Belarusian diamonds
“When the Chinese, Arabs and Israelis began to persuade us to sell the production, it became clear: there is demand”
On the edge of Atolino stands the same three-story factory building that is so talked about
Soviet scientists dreamed of an ordinary factory with painted walls and
freshly renovated inside. At the checkpoint here there is a policeman and a strict
access mode.
Several years ago, the Adamas BGU enterprise moved into the structure
Office of Presidential Affairs. A little bit more than a year back vice-rector
The Academy of Management under the President, Maxime Borda, was asked to evaluate
situation in Atolino: does it make sense to set up production there or is it easier
scrap the devices?
— I’ll admit right away: I’m a lawyer by training and the topic is diamond production.
“It was new for me,” Maxim Naumovich leads us into the workshop. - I became
study literature, watch Foreign experience. Honestly, I didn’t believe it myself
that our crystals are actually good and can be sold. But
traveled to exhibitions, showed diamonds, cut diamonds, which
grown in our workshop - the experts were delighted with the quality. And when
Armenians, Chinese, Israelis began to call with persuasion to sell
equipment, I finally understood: there are prospects.
So in November 2016, AdamasInvest LLC appeared (previous
The company is now at the stage of liquidation). It also obeys
Presidential Administration and works on a special project
“Restoring the production of synthesized diamonds and developing
jewelry production with inserts from the resulting diamonds.”
45 people work here.
— We received a loan for this project. The money is refundable, there are clear
deadlines,” emphasizes Maxim Naumovich. — We have developed a detailed
business plan, in six months the building was put in order, the workshop was restored and
launched jewelry production. In fact, that’s what we’re doing now
emphasis
According to Maxim Naumovich, it makes sense to go to the industrial diamond market
no: all the players were killed by China. Nine years ago Kyiv
The tool factory sold a sample of a special press to China. China
stamped 40 thousand of them, entered the technical market in 2014
diamonds and collapsed it 20 times. Therefore, even though
Belarusian industrial diamonds are superior in quality to Chinese ones, they cost
they are five times more expensive.
— China is not yet entering the jewelry market. I think they won't let him in
the largest players: US-controlled De Beers and Russian Alrossa.
Therefore, we have good chances in the synthesis of jewelry diamonds,” concludes
Maxim Bord.
Temperature can rise to 2 thousand degrees, pressure - up to 20 thousand atmospheres
A huge hall with dozens of cylinders and a minimum of workers - this is what a workshop with
the same BARS, of which there are 120 here. Service all devices for
a mechanic and an engineer can shift. In total, 10 people work in the workshop.
— They were designed in the 1970s, but in the production of diamonds for jewelry
targets and better than BARS have not yet been found,” shows an open hemisphere
Maxim Naumovich. — In general, there are currently two in the world
diamond production technologies: HTHP (high temperature, high pressure -
high temperature, high pressure) and CVD (chemical vapor deposition -
chemical vapor deposition). The latter is good for
production of industrial diamonds, but not very suitable for jewelry.
The fact is that in a gaseous environment the stone grows in even layers, and in
nature - unevenly, as with HTHP technology, which we
we use.
Maxim Naumovich shows the cylinder control panel. This
special equipment that is controlled manually. At the slightest
Deviations from the set values, workers adjust the indicators.
— It would seem that a computer could monitor how diamonds grow. And
To be honest, I had thoughts of automating this process, -
says the director. “But when I saw our technology, I realized:
there is no point. Firstly, it is expensive, the investment will not pay off. Secondly, growth
diamonds depends on a dozen nuances: for example, temperature changes
in the external environment at various stages. Will a computer be able to take all these into account?
nuances and react like a person? We think not yet.
The BARS themselves are designed quite simply: 3.5 tons of metal, a supply hose
oil, which creates pressure, and contacts, which provide current and temperature.
Inside the device there are two spheres: a large one and a smaller one. Each sphere consists of
six parts - punches made of special alloy
alloy Large ones weigh 16 kilograms, small ones - a little less
kilogram. Small punches are actually a consumable item. They
cost $200 and fail on average after five syntheses.
— Temperature at the entrance to the apparatus — 1500 degrees, pressure — 1800
atmospheres,” explains the director. — The temperature inside can rise to 2
thousand degrees, and pressure - up to 10-20 thousand. Temperature and pressure
change throughout the diamond's growth. This is three days, not
centuries, as in nature.
In the very center of the sphere there is a special porcelain cube. In him,
as Maxim Naumovich says, this is “all science.” Before the cube
sent to BARS, it is “stuffed”: they put in a special compressed
tablet consisting of individual components, usually metals,
here is also a small piece of diamond, which then grows into a large one
stone and graphite rod (graphite is the medium that gives the diamond
opportunity to grow). Then the cube is dried in the oven, soaked
certain materials, and only after all these procedures can it be
lay.
Whether a diamond will grow or not depends even on the warmth of the hands of the workers.
“Production technology is very capricious,” adds Maxim Naumovich.
— A diamond can grow big, maybe small, good or bad, but
it doesn't grow at all. It all depends on a dozen factors: the hands
the engineer who assembles the cube, on how he dries it,
whether it will impregnate correctly - down to the temperature in the workshop and quality
graphite Somehow they also tried to establish production in the Baltic countries.
We purchased equipment, but diamonds did not grow. It turned out that growing a diamond -
It's not just turning on a switch.
After three days, the cube is removed from the BARS, broken and a small
a blank on which the edge of the crystal can be seen. The blank is thrown into
flask and pour " royal vodka"(three portions of hydrochloric acid and one
nitrogen). The flasks are placed in a special cabinet and heated so that the reaction
went faster.
- Under normal conditions, after two hours the metals dissolve and
“Only the diamond remains,” they say in the laboratory. - Then we extract
diamond, wash it and dip it in the chrome mixture.
This is how the graphite is removed and a pure diamond is obtained. They weigh him
packaged and outsourced to a Russian company for cutting
(there are no free cutting specialists in Belarus, but it’s still time to train new ones
expensive).
— A diamond can lose 30-60% of its original weight. It all depends on
the presence of inclusions and the purity of the stone, they add in production. - Except
In addition, half of all syntheses are guaranteed to produce
high-quality stones for cutting and installation into a product - this is 220
stones per month. In another 20% of cases, the resulting stones are slightly lower
quality.
— It’s enough for work for now, but it’s not enough for development. Here we are fighting
on this task,” Maxim Naumovich shows samples of diamonds. - We
certified our stones at the International Gemological Institute in
Antwerp. Expert opinion is this: our stones are no different from
natural in all their chemical and physical characteristics. Here
exactly the same indicators in terms of strength, lack of reaction to radiation and
etc.
The company mainly grows colorless diamonds weighing up to 1 carat,
getting diamonds of 0.2-0.3 carats. Such stones are mainly used for
earrings and rings. Crystals can also be ennobled: given lemon,
black, red and other colors. But at the enterprise they say that Belarusians
prefer the classics.
“Hindus began to ask to make ritual diamonds from the ashes of the dead”
Having learned about the low prices for Belarusian stones by world standards,
the enterprise was called by Indians with an unusual request: to make ritual
stones.
— They want to preserve the memory of their cremated relatives in
in this form. Compared to a British company that comes close
engaged in similar production, our diamonds were produced five times
cheaper,” explains the director.
— We did not dare to work with the ashes of the dead, but the technology for obtaining
diamonds made from hair were worked out. Yes, diamonds can be obtained from hair. We
We get carbon from them, and then we work according to the same scheme. Technology
We have tested and released 12 such stones. True, it’s still massive
The implementation of this topic is the next stage of work for us. And in this thread
great potential for science.
But still, the company places its main emphasis on its own jewelry
production. The jewelry workshop, although small (9 people), is
potentially they can produce up to 5 thousand units per month. Last
This week a large batch of Belarusian diamonds arrived in stores.
— Our products are 20-30% cheaper than products with natural
stones, and the synthesized diamonds themselves cost half as much
natural. For example, the selling price for ready product with diamond in
0.15 carats is 300 rubles, with a stone of 0.25 carats it will cost
600 rubles,” the director shows samples of products.
These are mostly engagement rings. Maxim Naumovich says that there are plans
there are earrings, cufflinks, silver with diamonds, and even an art series in
ecostyle.
— In Europe, synthesized diamonds are gaining popularity. It is believed that
they are more environmentally friendly than those extracted from the bowels of the earth. And it is true. Especially
that their properties are not inferior to natural ones,” he argues and shares
plans: to gain a foothold in the jewelry market, open a branded store with
prices 40% lower than market prices and much more.
— There is a goal to make our diamonds an affordable Belarusian brand. A
the global task is to further develop scientific research using the profits received
technologies in this area,” adds Maxim Bord.
